Quincy mother found insane in poisoning death of 8-year-old boy

A judge on Tuesday acquitted a Quincy woman of murdering her 8-year-old son by lighting a charcoal fire in a barricaded bedroom in their Germantown apartment during what prosecutors said was an attempt to kill herself, too.

A judge on Tuesday acquitted a Quincy woman of murdering her 8-year-old son by lighting a charcoal fire in a barricaded bedroom in their Germantown apartment during what prosecutors said was an attempt to kill herself, too.

After a jury-waved trail, Norfolk Superior Court Judge Robert C. Cosgrove found Li Rong Zhang, 42, not guilty by reason of insanity of the 2011 killing of her son, Brandon Yang, on Tuesday, according to the Norfolk County district attorney’s office.

During the trial, multiple medical experts testified that Zhang lacked criminal responsibility at the time of the incident and that she exhibited psychotic depression with paranoid delusions and acute suicidality, according to the district attorney’s office. The judge also heard testimony that Zhang had been diagnosed with paranoid schizophrenia in 2010.

Zhang was taken to Worcester State Hospital for evaluation and treatment after the verdict.

On Jan. 13, 2011, Zhang was found unresponsive inside a locked and barricaded bedroom in her family’s 19 Yardarm Lane apartment. Her son, Brendan Yang, was lying face down on a bed. Also inside the room was a silver charcoal-fired wok that prosecutors said she planned to use to kill both herself and her son. She survived, but the boy died from the poisonous fumes.